sgr ms thesis - University of Maine

4.3.1. Model Setup
The model is used to produce a maximum temperature gradient with
distance into the metamorphosed zone, and to compare these results with
observed isograd data. This comparison will allow us to constrain the thermal
evolution of the Cadillac Mountain intrusive complex and surrounding wall rock.
The thermal evolution of the wall rock surrounding the intrusion was solved
numerically by use of COMSOL Multiphysics (www.comsol.com), a finite element
program equipped with a conductive heat transfer module. Behavior of the
thermal conductive system is dependent on the thermal conductivity, specific
heat, and density of the intrusion and wall rock as well as latent heat of fusion for
the crystallizing intrusion, endothermic metamorphic reactions in the wall rock
that consume heat energy, the initial intrusion temperature, and the initial wall
rock temperature during emplacement (Jaeger, 1961; Johnson et al., 2011).
It must be noted that the Cadillac Mountain intrusive complex was
emplaced around 2-5km depth, so the wall-rock thermal evolution was probably
affected by convective flow of water (e.g Walther, 1990; Johnson et al., 2011).
Also, the duration of intrusion activity plays an important role in determining
maximum temperature for contact metamorphism. Multiple dike-fed
emplacements are common for shallow intrusives, and the gabbro-diorite sheets
that form the base of the Cadillac Mountain intrusive complex are evidence for
this type of activity (Jellinek and DePaolo 2003, Glazner et al. 2004, Cruden
2005, Bartley et al. 2006, Lipman 2007, Walker et al. 2007, Michel et al. 2008,
Miller 2008). Plutons reinvigorate with the continued introduction of magma,
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